(1) Field of the Invention
This invention relates to an automatic locking retractor suitable for use in a vehicle seat belt, and more particularly to such a retractor which produce little unpleasant noise when winding the webbing into the retractor.
(2) Description of the Prior Art
In a vehicle seat belt equipped with a so-called automatic locking retractor, the webbing wound up on the retractor is pulled out and worn by the occupant. The webbing is then allowed to be wound back on the retractor over any extra length thereof. When the occupant tries to pull out the webbing again, the webbing is restrained from any further release. A variety of different types of such automatic locking retractors has been proposed and actually used to date (see, for example, U.S. Pat. No. 3,412,952 issued Nov. 26, 1968 to Wohlert et al, U.S. Pat. No. 3,667,698 issued June 6, 1972 to Fisher, U.S. Pat. No. 3,944,163 issued Mar. 16, 1976 to Yoshio Hayashi et al, etc.).
Many of such prior art automatic locking retractors are of such a type that they are each constructed of a pair of cog wheels integral with a take-up spindle, on which a webbing is releasably wound up, and a lock lever normally urged or biased in a direction capable of engaging with the cog wheels and controlled by a cam plate which is frictionally cooperated with the rotation of the take-up spindle.
In the above conventional structure, the relationship between the biasing force applied to the lock lever and the frictionally-produced turning force of the cam plate is extremely delicate. Therefore, it is necessary to pay close attention to the quality control of the spring means which are employed to produce the biasing force and turning force.